JMHO, but they are both 4 lbs less than they were expected to be. One or two pounds okay, but 4 is more than half the amount they were expected to be. Just as a precaution, I'd be running kidney and liver tests on them, to rule out any problems with their metabolism.
If they're fine, then I'd ask the vet to access their overall body condition:
Body Condition Scoring Chart | College of Veterinary Medicine to be sure their frame can handle additional weight. If it can't, additional weight will put undue stress on the leg and hip joints.
I can't say yes or no to your question without seeing them and doing a hands-on exam to access their actual body condition, and proportions.
I do know that when changing a diet to either lose or gain weight, it should be done gradually, and their weight should be checked on a regular basis to make sure you're getting the expected results.